The present invention relates to a fuel cell and an electronic apparatus with the same mounted thereon. More particularly, the present invention relates to a fuel cell and an electronic apparatus with the same mounted thereon in which various apparatuses for stably performing power generation by a fuel cell or cells are contained in a compact form.
A fuel cell is a power generation device for generating electric power by an electrochemical reaction between a fuel, such as hydrogen gas, and an oxidant such as oxygen contained in air. In these years, the fuel cells have been paid attention to as a power generation device free of environmental pollution, since the product upon power generation therein is water, and the use of a fuel cell as a drive power source for driving a vehicle, for example, has been tried.
Furthermore, the application of a fuel cell is not limited to the above-mentioned drive power source for driving automobiles, and the development of fuel cells as drive power sources for portable electronic apparatuses such as notebook type personal computers, cellular phones and PDAs has been made vigorously. It is important for these fuel cells to be capable of stably outputting required electric power and to have such size and weight as to be portable, and a variety of technical developments have been carried out vigorously.
In addition, the quantity of electric power outputted from a fuel cell can be enhanced by joining a plurality of power generation cells (unit cells). For example, there has been developed a fuel cell in which a joint body having electrodes provided on both sides of a solid state polymer electrolyte membrane is clamped between separators to form a power generation cell, and such power generation cells are laminated to form a stack structure.
Meanwhile, at the time of generating electric power by the fuel cell configured as above, it is necessary for the solid state polymer electrolyte membrane to conduct protons therethrough and it is important for the solid state polymer electrolyte membrane to be moistened appropriately.
However, the power generation reaction in the fuel cell is an exothermic reaction, and the portion where the power generation reaction occurs vigorously tends to be brought to a high temperature. Therefore, there are cases in which the amount of water contained in the solid state polymer electrolyte membrane is decreased attendant on the driving of the fuel cell, with the result of a trouble in stable power generation in the fuel cell.
On the other hand, water is produced by the electrochemical reaction at the time of power generation. Where water is accumulated in the conduit for a fuel gas formed in the separator, the conduit may be clogged with water to hamper smooth flow of the fuel gas in the conduit. Where smooth flow of the fuel gas is not achieved in the conduit, it is difficult to sufficiently supply the fuel gas into the plane of the joint body, so that the power generation by the fuel cell cannot be performed satisfactorily.
The above-mentioned two problems show that it is difficult to simultaneously achieve both the restraint of the temperature rise in the fuel cell at the time of power generation by the fuel cell and the control of the amount of water contained in the fuel cell. Therefore, there is a demand for a technology by which these problems can be solved at the same time. Particularly, in the fuel cell having the stack structure, there is a demand for a technology by which a smooth flow of the fuel gas in the conduits formed in a plurality of separators is achieved, and oxygen-containing air is taken in from the exterior of the fuel cell so as to bring the joint body constituting the fuel cell into the state of being moistened appropriately, making it possible to stably outputting the required electric power.
Besides, where a fuel cell is used for driving a portable electronic apparatus, it is desirable that the fuel cell is also portable, and there is a demand for a fuel cell which is capable of stable power generation and which has been reduced in size.